Sysadmin > UtilitIes > RsynC > RsyncIsYourShellClean

# rsync -avz -e ssh 192.168.1.10:bin .
Password for user@host:
protocol version mismatch -- is your shell clean?
(see the rsync man page for an explanation)
rsync error: protocol incompatibility (code 2) at compat.c(178) [Receiver=3.1.2]

Check your shell with

ssh 192.168.1.10 false

if you see some output you know which script to blame.